Nazis using the remains of Jews to repair Russian roads and fertilize Russian fields. Apparently

"the Hitlerites began to destroy the traces of their crimes. They exhumed and burned corpses, ground bones, and strewed the ashes on the fields; they also used the slag formed by the corpses cremated, as well as the bone flour, for repairing the roads and fertilizing the fields."

From Nuremberg (must be true)